Mesh Through Control Joints

For years we scoured the net looking for any published results for what happens when a Steel Mesh path is subjected to uplift and could find nothing - So we did it ourselves.

The reason is we want to sell our product TripStop and we continually run into the fact many Cities and Councils specify Steel mesh in the belief it will stop future trip hazards. In particular in design manuals where groups of Cities and Councils put together a plan on how best to build a sub-division. They then share the common knowledge which is a good thing if the knowledge makes good engineering sense.

Proving up the theory that Steel Mesh will fail in a concrete path that is subjected to uplift [from tree roots and/or soil movement] took us many years and over $50k to do.

Before we did the actual independent test we did many 'in house' tests to find the best method to be able to visually show what must happen. That is the path must hinge on the base of the concrete path when uplifted, the extreme pressure spalls some of the concrete under the concrete but the main pressure is put on the Steel Mesh itself which must stretch and with under 2000 kgs of pressure and enough uplift snaps the entire mesh sheet resulting in total joint failure. How long all this will take will depends on many factors. How aggressive the tree roots are, how expansive is the soil, how wet is the environment and so on.

In an area such a Melbourne Australia where TripStop was invented which is generally heavily treed, on expansive soils and wet makes it a perfect for early mesh failure. Bottom line, in Melbourne at least either the mesh will snap or the mesh will corrode well short of the 50 year time frame a concrete path is generally expected to last.

For the life of me I cannot understand how Mesh can be specified like this in public infrastructure when all engineers know it's against all good engineering standards to run mesh thru joints.

AS 3727 8(e) clearly states this.

The main reason is of course corrosion of the Mesh and the resulting concrete cancer which is why the mesh must be covered by at least 50mm of concrete. Now we have proven and know there is a second reason.